Make initialization of the QuicInMemoryCache explicit to avoid spooky action at a distance which co…

net/tools/quic/quic_server.cc

Index: net/tools/quic/quic_server.cc
diff --git a/net/tools/quic/quic_server.cc b/net/tools/quic/quic_server.cc
index 371c92b4995032ee184f57d2fff56abc6156f9ff..8bc0e81e38f15a4b77741c2d97a7eed8109b4f22 100644
--- a/net/tools/quic/quic_server.cc
+++ b/net/tools/quic/quic_server.cc
@@ -40,9 +40,13 @@
 
 namespace net {
 namespace tools {
-
 namespace {
 
+// Specifies the directory used during QuicInMemoryCache
+// construction to seed the cache. Cache directory can be
+// generated using `wget -p --save-headers <url>`
+std::string FLAGS_quic_in_memory_cache_dir = "";
+
 const PollBits kEpollFlags = PollBits(NET_POLLIN | NET_POLLOUT | NET_POLLET);
 const char kSourceAddressTokenSecret[] = "secret";
 
@@ -95,8 +99,11 @@ void QuicServer::Initialize() {
   }
 
   epoll_server_.set_timeout_in_us(50 * 1000);
-  // Initialize the in memory cache now.
-  QuicInMemoryCache::GetInstance();
+
+  if (!FLAGS_quic_in_memory_cache_dir.empty()) {
+    QuicInMemoryCache::GetInstance()->InitializeFromDirectory(
+        FLAGS_quic_in_memory_cache_dir);
+  }
 
   QuicEpollClock clock(&epoll_server_);